These draft guidelines include new recommendations about the treatment of obesity. In particular, NICE advises that those with recent-onset type 2 diabetes who fulfil certain body mass index (BMI) criteria should have surgery. The recommendations also provide guidance on the use of very low-calorie diets.

As is often the case, the proposed NICE recommendations have made a huge media splash, leading to front-page headlines such as the Daily Mail's claim that, "Thousands more to get obesity ops on the NHS".

These are draft guidelines, so it is far from certain whether they will become official advice. A consultation will be taking place between July 11 and August 8 2014.

What are the main new draft guidelines?

Currently, bariatric surgery is offered to people with a BMI of 40 or more, or those with a BMI between 35 and 40 if they also have another significant and possibly life-threatening disease that could be improved if they lost weight, such as type 2 diabetes or high blood pressure.

Patients must have tried and failed to achieve clinically beneficial weight loss by all other appropriate non-surgical methods and be fit for surgery. This recommendation has not changed.

The updated draft guidelines include additional recommendations on bariatric surgery for people with recent-onset type 2 diabetes. These recommendations include:

Offering an assessment for bariatric surgery to people who have recent-onset type 2 diabetes and are also obese (BMI of 35 and over).

Considering an assessment for bariatric surgery for people who have recent-onset type 2 diabetes and have a BMI between 30 and 34.9. People of Asian origin will be considered for surgery if they have a lower BMI than this, as the point at which the level of body fat becomes a health risk varies between ethnic groups. Asian people are known to be particularly vulnerable to the complications of diabetes.

What is bariatric surgery?

A range of techniques are used, but they are usually all based on the principle of surgically altering the digestive system so it takes less food and makes the patient feel fuller quicker after eating.

The two most common types of weight loss surgery are:

gastric band – where a band is used to reduce the size of the stomach so a smaller amount of food is required to make someone feel full

gastric bypass – where the digestive system is rerouted past most of the stomach so less food is digested, which makes the person feel full

It is estimated the risk of dying shortly after gastric band surgery is around 1 in 2,000. A gastric bypass carries a higher risk of around 1 in 100.

The surgery also carries the risk of other side effects, including:

excess skin – removal of excess skin is usually considered a form of cosmetic surgery, so it is not usually available on the NHS

gallstones – small stones, usually made of cholesterol, that form in the gallbladder

stomal stenosis – where the hole that connects the stomach to the small intestine in people with a gastric bypass becomes blocked

gastric band slippage – where the gastric band slips out of position

food intolerance

psychosocial effects – for example, some people have reported relationship problems with their partner because their partner begins to feel nervous, anxious or possibly jealous of their weight loss

What other treatments have new draft recommendations?

The draft guideline also makes recommendations regarding very low-calorie diets (800kcal per day or less). These include:

Not routinely using very low-calorie diets to manage obesity.

Only considering very low-calorie diets for a maximum of 12 weeks (continuously or intermittently) as part of a multicomponent weight management strategy with ongoing support. This would be for people who are obese and have a clinically assessed need to rapidly lose weight – for example, people who require joint replacement surgery or who are seeking fertility services.

Giving counselling and assessing people for eating disorders or other mental health conditions before starting them on a very low-calorie diet. This is to ensure the diet is appropriate for them.

The risks and benefits of surgery should also be discussed. Patients should be made aware that very low-calorie diets are not a long-term weight management strategy and that regaining weight is likely, but not because of a failure on their or their clinician's part.

How were the draft recommendations received?

There is concern about how many people will be eligible for treatment under the new guidelines and how much it will cost, with Diabetes UK estimating that 850,000 people could be eligible for surgery.

Simon O'Neill, from the charity Diabetes UK, has been quoted as saying that, "Bariatric surgery should only be considered as a last resort if serious attempts to lose weight have been unsuccessful and if the person is obese.

"It can lead to dramatic weight loss, which in turn may result in a reduction in people taking their type 2 diabetes medication, and even in some people needing no medication at all.

"This does not mean, however, that type 2 diabetes has been cured. These people will still need to eat a healthy balanced diet and be physically active."

What is the rationale behind the new recommendations regarding bariatric surgery?

Professor Mark Baker, director of the Centre for Clinical Practice, said that, "Updated evidence suggests people who are obese and have been recently diagnosed with type 2 diabetes may benefit from weight loss surgery.

"More than half of people who undergo surgery have more control over their diabetes following surgery and are less likely to have diabetes-related illness; in some cases, surgery can even reverse the diagnosis. The existing recommendations around weight loss surgery have not changed."

It could actually be the case that increasing access to bariatric surgery will save the NHS money in the long term if this helps combat the obesity epidemic.

If obesity levels continue to rise at their current rates, it is estimated that by 2050 the annual cost of treating obesity-related complications will be £50 billion, more than half the entire current NHS budget for England; 1 million operations at £5,000 each – £5 billion in total – could well seem a bargain in comparison.